Sustainable silicates and methods for their extraction

Abstract

Liquid silicate products derived from processed organic plant matter ( 112 ), such as rice hulls, have improved purity and properties for use in the production of higher purity amorphous silica compositions ( 180 ). The liquid silicate can be optically clear, can have a controlled ratio of silica to metal earth oxide components, and can have lower concentrations of undesirable contaminants such as aluminum, chloride, iron, sulfate, and titanium.

The invention claimed is: 
     
         1 . A target sodium silicate solution, comprising:
 sodium silicate converted from biogenic silica in an amorphous state with sodium hydroxide, wherein the biogenic silica is from rinsed ash of burned organic matter; and   water, wherein the target sodium silicate solution has a ratio R of SiO 2 :Na 2 O by weight that is greater than or equal to 1.8, wherein the target sodium silicate solution has lower equivalent concentrations of contaminants and/or impurities when compared to a standardized sodium silicate solution, the lower equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution including a combined chloride ion and sulfate ion concentration that is an equivalent concentration to less than or equal to 250 ppm and a total organic content that is an equivalent concentration to less than approximately 30 ppm in the standardized sodium silicate solution;   wherein the standardized sodium silicate solution has approximately 37% solids by weight and has a ratio R by weight of SiO 2  to Na 2 O that is approximately 3.3; and   wherein the rinsed ash of burned organic matter has been rinsed with clean water and separated from contaminated rinse water, the contaminated rinse water containing chlorides, sulfates, and other water soluble contaminants.   
     
     
         2 . The target sodium silicate solution of  claim 1 , wherein the combined chloride ion and sulfate ion concentration in the target sodium silicate solution is an equivalent concentration to less than or equal to 100 ppm in the standardized sodium silicate solution. 
     
     
         3 . The target sodium silicate solution of  claim 1 , wherein the target sodium silicate solution has 10 to 50% of sodium silicate by dry content weight. 
     
     
         4 . The target sodium silicate solution of  claim 1 , wherein the target sodium silicate solution has 35 to 50% of sodium silicate by dry content weight. 
     
     
         5 . The target sodium silicate solution of  claim 1 , wherein the biogenic silica is from ash of burned rice hulls. 
     
     
         6 . The target sodium silicate solution of  claim 1 , wherein the target sodium silicate solution is produced from rice hull ash, and wherein the silica is maintained below a temperature of 200° C. 
     
     
         7 . The target sodium silicate solution of  claim 1 , wherein the target sodium silicate solution is produced from rice hull ash, and wherein the amorphous silica is converted to silicate at or below 160° C. 
     
     
         8 . The target sodium silicate solution of  claim 1 , wherein the target sodium silicate solution has a ratio R of SiO 2 :Na 2 O by weight that is greater than or equal to 3.22. 
     
     
         9 . The target sodium silicate solution of  claim 1 , wherein the target sodium silicate solution has a ratio R of SiO 2 :Na 2 O by weight that is greater than or equal to 3.75. 
     
     
         10 . The target sodium silicate solution of  claim 1 , wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a percentage of undissolved solids by weight that have a minimum dimension greater than 2 microns, wherein the percentage of such undissolved solids is an equivalent concentration to less than or equal to 0.001% in the standardized sodium silicate solution. 
     
     
         11 . The target sodium silicate solution of  claim 1 , wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a chloride ion concentration that is an equivalent concentration to less than 100 ppm in the standardized sodium silicate solution. 
     
     
         12 . The target sodium silicate solution of  claim 1 , wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a sulfate ion concentration that is an equivalent concentration to less than 100 ppm in the standardized sodium silicate solution. 
     
     
         13 . The target sodium silicate solution of  claim 1 , wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a calcium concentration that is an equivalent concentration to less than 25 ppm in the standardized sodium silicate solution. 
     
     
         14 . The target sodium silicate solution of  claim 1 , wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a magnesium concentration that is an equivalent concentration to less than 10 ppm in the standardized sodium silicate solution. 
     
     
         15 . The target sodium silicate solution of  claim 1 , wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include an aluminum concentration that is an equivalent concentration to less than or equal to 50 ppm in the standardized sodium silicate solution. 
     
     
         16 . The target sodium silicate solution of  claim 1 , wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution includes an iron concentration that is an equivalent concentration to less than or equal to 25 ppm in the standardized sodium silicate solution. 
     
     
         17 . The target sodium silicate solution of  claim 1 , wherein the target sodium silicate solution has a nephelometric turbidity that is equivalent to less than 2 units in the standardized sodium silicate solution. 
     
     
         18 . The target sodium silicate solution of  claim 1 , wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a total organic content that is an equivalent concentration to less than approximately 20 ppm in the standardized sodium silicate solution. 
     
     
         19 . The target sodium silicate solution of  claim 1 , wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include equivalent concentrations of less than or equal to: 100 ppm chloride ion, 50 ppm calcium, 50 ppm sulfate ion, 75 ppm aluminum, 50 ppm iron, and 10 ppm titanium in the standardized sodium silicate solution,
 wherein the target sodium silicate solution has concentrations equivalent to the standardized solution having a nephelometric turbidity that is less than 2.   
     
     
         20 . The target sodium silicate solution of  claim 1 , wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a percentage of undissolved solids by weight that have a minimum dimension greater than 2 microns, wherein the percentage of such undissolved solids is an equivalent concentration to less than or equal to 0.001% in the standardized sodium silicate solution, wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a chloride ion concentration that is an equivalent concentration to less than 100 ppm in the standardized sodium silicate solution, wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a sulfate ion concentration that is an equivalent concentration to less than 100 ppm in the standardized sodium silicate solution, wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a calcium concentration that is an equivalent concentration to less than 25 ppm in the standardized sodium silicate solution, wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a magnesium concentration that is an equivalent concentration to less than 10 ppm in the standardized sodium silicate solution, wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include an aluminum concentration that is an equivalent concentration to less than or equal to 50 ppm in the standardized sodium silicate solution, wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include an iron concentration that is an equivalent concentration to less than or equal to 25 ppm in the standardized sodium silicate solution, wherein the target sodium silicate solution has a nephelometric turbidity that is equivalent to less than 2 units in the standardized sodium silicate solution, and wherein the equivalent concentrations of contaminants and/or impurities in the target sodium silicate solution include a total organic content that is an equivalent concentration to less than approximately 20 ppm in the standardized sodium silicate solution.